import { describe, it, expect, vi, beforeEach } from 'vitest'
import { asyncHandler } from '../asyncHandler'
import type { Request, Response, NextFunction } from 'express'

describe('asyncHandler', () => {
  const mockReq = {} as Request
  const mockRes = {} as Response
  const mockNext = vi.fn()

  beforeEach(() => {
    vi.clearAllMocks()
  })

  describe('成功调用', () => {
    it('应正常执行函数并返回结果', async () => {
      const mockHandler = vi.fn().mockResolvedValue('操作成功')
      const wrappedHandler = asyncHandler(mockHandler)

      await wrappedHandler(mockReq, mockRes, mockNext)

      expect(mockHandler).toHaveBeenCalledWith(mockReq, mockRes, mockNext)
      expect(mockNext).not.toHaveBeenCalled()
    })

    it('应处理返回同步值的函数', async () => {
      const mockHandler = vi.fn().mockResolvedValue({ id: 1, name: 'test' })
      const wrappedHandler = asyncHandler(mockHandler)

      await wrappedHandler(mockReq, mockRes, mockNext)

      expect(mockHandler).toHaveBeenCalled()
      expect(mockNext).not.toHaveBeenCalled()
    })
  })

  describe('异常传播', () => {
    it('应正确传播异步错误', async () => {
      const asyncError = new Error('异步错误')
      const mockHandler = vi.fn().mockRejectedValue(asyncError)
      const wrappedHandler = asyncHandler(mockHandler)

      await wrappedHandler(mockReq, mockRes, mockNext)

      expect(mockHandler).toHaveBeenCalled()
      expect(mockNext).toHaveBeenCalledWith(asyncError)
    })

    it('应处理 Promise.reject 的错误', async () => {
      const error = new Error('Promise rejected')
      const mockHandler = vi.fn().mockReturnValue(Promise.reject(error))
      const wrappedHandler = asyncHandler(mockHandler)

      await wrappedHandler(mockReq, mockRes, mockNext)

      expect(mockNext).toHaveBeenCalledWith(error)
    })

    it('应处理非 Error 对象的异步错误', async () => {
      const error = '字符串错误'
      const mockHandler = vi.fn().mockRejectedValue(error)
      const wrappedHandler = asyncHandler(mockHandler)

      await wrappedHandler(mockReq, mockRes, mockNext)

      expect(mockNext).toHaveBeenCalledWith(error)
    })
  })

  describe('函数调用时机', () => {
    it('应立即调用底层函数', () => {
      const mockHandler = vi.fn().mockResolvedValue('result')
      const wrappedHandler = asyncHandler(mockHandler)

      wrappedHandler(mockReq, mockRes, mockNext)

      expect(mockHandler).toHaveBeenCalled()
    })
  })
})